“Yeah, I touched the leather, but I didn’t touch the end zone,” Mathieu said after the 27-20 loss in the opener. “We lost by seven points, so that’s how I look at it and how I judge myself.”

A free agent who signed with the Texans after spending the first five years of his career in Arizona, Mathieu was Houston’s biggest offseason acquisition. The signing seemed to pay off in his very first game.

Brady dropped back near his own goal line and took aim for running back James White across the middle. But defensive lineman Angelo Blackson deflected the ball, and Mathieu reached behind him to grab it as he went to the turf.

“That’s why we brought him here,” coach Bill O’Brien said. “We think he’s an instinctive player, from what I can see.”

Blackson said he anticipated that Brady would try to step up in the pocket and throw, so the goal was to get a hand in his face. The ball went off Blackson’s hand and fluttered downward before Mathieu grabbed it at the 17.

But the Texans missed a chance to take advantage of the field position, losing seven yards before settling for a field goal that cut the deficit to 7-3. In the third quarter, Brady connected with Rob Gronkowski for a 25-yard reception before the Patriots tight end was hit by Kareem Jackson and lost the ball.

Mathieu scooped it up. The Texans advanced to the New England 17 but turned the ball over on downs.

“He’s a great player,” defensive lineman J.J. Watt said. “We knew we were getting a great player and a guy that can change games and he did a great job today. With the pick, the fumble recovery, that’s another guy that can make game-changing plays and the more we can of that, and the more we can all start to do our part in that, the better we’re going to be.”

A year after losing to the Patriots 36-33, O’Brien returned to New England with a healthy team that had hopes of beating his former mentor.

Watt returned after playing only five games last season because of a broken leg, and Whitney Mercilus also returned from a torn pectoral muscle that put him on injured reserve in 2017.

With Jadeveon Clowney recovering from knee surgery following the best season of his career and Mathieu joining the secondary, the Texans’ defense was a strong point.

And with Deshaun Watson (176 yards passing, 40 running) also returning from an injury after a stellar start to his rookie year, the offense figured to be dangerous, too.

But Brady and Gronkowski carved up the Texans at the worst times, including a two-minute drill at the end of the first half after taking over at their own 22 with just 88 seconds on the clock. Brady completed 5 of 6 passes on the drive, hitting Phillip Dorsett on a 4-yard touchdown pass that extended the New England lead to 21-6.

“To give up that touchdown, it is very frustrating,” Clowney said. “I am very upset right now. I hate losing and I hate playing bad and all of that. I know I’ve got a lot of season left and a lot of improvement to do.”